Chain link side bar, or the like, having extruded locking lugs



Nov. 12, 1940. Y c. F. LAUENSTEIN CHAIN LINK SIDE BAR, OR THE LIKE, HAVING EXTRUDED LOCKING LUGS Filed Dec. 13, 1958 (m/Hmezzsfez);

stock of proper section, shaping the blanks beextruded lugs couldbe produced which are as 20 Patented Nov. 12,1940 t I UNITED A E PArlzrrr OFFICE Carl Fl Lauenstein, Indianapolis, Ind., assignor to Link-Belt Company, a corporation of Illinois a ApplicationfDecemberxl3, 1 938, Serial No. 45,519

3 cl i s (01. 74-250) 1 This invention relates to new and useful imv lugs of approximately squareor rectangular shape provements in chain link side bars or other load in plan were employed on cast or drop forged side bearing elements, which are provided with proplates, the same shaped lug was adopted when the jecting pin locking lugs, or other projections, extruded lugs were developed andnormalshop produced by extruding or. displacing material practice dictated that thewdepressions should be 5 from the bodies of the elements. a, of the same general shape as the lugs to provide It has been the practice for many years to proproper grain flow in the material of the side bars videso'me form of locking lug'on chain link side during the extruding operation. y bars for engaging flat surfaces provided on the Chain link side bars with many different 10 heads of chain pins to prevent rotation of the shaped lugs and depressions, including different 10- pins during joint articulation. It has been acombinaions, of the same, were made and tested simple matter to form these locking lugs as in and, as a resultlof such experiments, it-wasas .tegral parts of cast or drop forged side bars for certained that as sharp copners or angles par- I the casting molds'or forging dies merely have ticularlyinrthe depressions weremodified or elim- I been shaped to provide an appropriate increase inated, failures became less frequent. A combi- 15 in thickness at the location of the lugs. nation depression and lug shapev was finally de- When forming chain link side bars by the veloped-tpwhich vso materially improved the rather recently adopted, less expensive method strength of side bars in'the region of the depresn involving cutting the side bar blanks from bar sion and locking lugs that side bars having such 5 tween"dies when tnecessary, for example, in formstrongI as side bars without any locking lugs. It ing offset link sidebars, and perforating and wasdefinitely established, therefore, that side breaching the shaped blanks to form pitch or barshaving extruded locking lugshcouldbe prochain pinlholes,the locking lugs must be formed duped which were not renderedrless serviceable from thematerialof the original sectionof the as a resultof the extruding or displacing ofmate- 25 bar stock and the lugs'are produced by extrudrialfrom the bodyof the side bars. L a ing or displacing an appropriate amountof the The primary object-of this invention is to promaterial laterallyof the bodies of the side bars, vide chain link side bars, or other load bearing Thislateral displacement of the materialtoform elements, @with extruded locking. lugs without the projecting'locking lugs naturally results in weakening the said bars in the regions of the 30 the formation of depressions in the faces or the rugs." H a 7 n side bars opposite to the lugs. a n Afu'rtherobject of the invention is to provide Unlike the cast or drop forged lugs, the exatype of depression which i's produced in a chain truding of lugs fromfthe materialof the side bars linkside bar, or the like, [informing an extruded 5 heretofore has definitely weakened said bars. locking lugyor other projection, without weak- Considerable"troublejhas been experienced" with e'ning thesidebar.

sidebars having such extruded lugs for failures 7 Qther b and advantages of theinvention have developed due to progressive fractures ongiwiuibve} apparent during the course of the follow? M nating 1171 the depressions and progressing outping aesriptiom r v- 40 wardly across the side bars. The fact thatthe extrusion of locking lugs has a weakening effect on side bars was more or less to be expected However, the percentage of failures and their 00- a currence so soon afterplacing a new chainin I we x "15 service indicated that such side bars were weak-' f' Q a la a m1nnk havlng; 5

ened to a greater extent than should be expected. hg' n a 5 r funcilons 1 9 a Therefore, experiments were conducted to deter- P aga'1 n5t q w j mine if the life of side bars having extruded am 5 ,Slde lf a of h t r locking lugs could be materiallyflengthened. Structure n F a; 1, y As all failures resulted from fractureswhich Fi uret isafrasrri nt rnenlarged elevational 50 i started at the sides of the. depression and pro view of the innerside of the chain link sidebar gressed outwardly, it was thought that the shape disclosed in Figs; 1 and 2 which is provided with kiln the accompanying drawing forming a part 40 of-ithis specification and inilwhich like numerals" are employed to esignate like parts throughout of the tools which formed the lug and the de f thepin lockinglu'g, a t l pression and/or the shapecf the resultant lug Figure 4 is a longitudinal sectionalview taken I and depression might-be the cause. Aslockina online 4=-4 of'Fig. 3;

* to the desired section of-the side bars, shaping the I line 88 of Fig. 7.

formed while themet alofthe sidebar'is either In the drawing, wherein for the pu pose of illustration is shown the preferred embodiment of this invention, and particularly referring to Figs. 1 and 2, there is disclosed aconventional type of offset chain link of the roller type which has beenselected as representative of chain link structures which employ articulatingjoint pins that are held against rotation by locking lugs. This chain includes a side bar I0, formed without a locking lug, and a side bar H which is provided with an extruded locking lug l2. As is conven: tional with this type of link, a bushing i3 is received insuitable pitch holes: formed in the inner ends of the side bars. This bushingfunctions to exteriorly journal'or supporta roller i4 and to receive in-its bore the chain pin of the next adjacent link. The remaining or outside ends of the side bars are provided with suitable pitch holes l5 and--l6-to receive an articulating joint pin ll. head 18 of the pin H is provided with one or 5 more ,flat faces or surfaces I9." The projecting lug I2 engages'one of these flat faces of the pin to prevent rotation of the pin during joint articulation-of thelink". The side bars of ch'ain linksof the character 1 disclosed in Figsfl and -2 may be formed either by casting or drop forging operations or by the more recently developed and less expensive method involving cutting the side bars from a piece of bar stock which has-a section corresponding side barsw'hen necessary, and perforating and breaching the side bar blanks to formthe'desired pitch holes. W hen alocking lug is to be formed on' a side bar of the type which is cut from bar stock, it isnecessary to form the locking lug fromthe original material of theside bar blank. An appropriate amount of the material of the blank must be extruded ordisplaced laterally, by a forcing or forming'operation which is perhot or cold, depending upon the thickness of the stock, etc. The extrudedlugs are forged or formed, either hot or cold, by means of adie, which is shaped to produce the desired lug formato produce the depression whichmustbe formed indisplacing a suflicient amount of the material of the bar blank to produce the desired, projecting lug.

' When themethod of producing chain link side barshaving extruded locking lugs was adopted, it was only natural that the locking lugs be given the generally square or rectangular shape of the locking lugs which have ,been conventionally .formed on cast or dropforged side bars. Figs.

, 6 to 8, inclusive, illustrate this first adopted form r of extruded locking lugs. h

Fig. 6 discloses, by means-of dash lines 20, the

shape, in plan, of the projecting locking lug 2|,

see Figs. 7 and 8. Fig. 6 also discloses in full lines, the shape of the depression 22.

Although the method of producing chain side bars which involved the step of extruding locking lugs was a less expensive way of As is clearly illustrated in Fig. 2, the

link

facturing chain links, the side bars having the extruded locking lugs were found to be considerably weaker than the side bars which were not provided with such lugs. In any given chain assembly, it was found that many of the side bars having the extruded lugs would fail before a failure would occur in any of the side bars not provided with the locking lugs. It was further determined that the failures always resulted from progressive fractures which started at the corners 23 of the depression 22, see Fig. 6, and progressed laterally outwardly to the side edges of the bars, as indicated by the lines 24. It was decided, therefore, that the shape of the tools and the resultant shape, particularly of the depression 22, might be thecause of these failures. Numerous chain link side bars with differently shaped lugs and depressions were made and tested. It was determined that as sharp corners and angles were modified or eliminated, fewer failures occurred and the life of side bars having extruded lugs more closely approached the life of side bars which were not provided with lookin lugs.

It willbenoted by inspecting Figs. 6 to 8, inclusive, that the depression 22 is provided with sharp corners 25 which extend substantially at right angles to the plane of the face of the side bar. Sharp corners or angles 26 also were formed at the juncture of the side walls and the bottom wall of the depression. The lug 2| also is formed with several sharp corners and angles. It appeared that these sharp corners and angles had a very definite weakening elfectand the elimination of such sharp corners or angles definitel lessened the percentage of failures.

Finally, the shape of lug and depression, 315- formed in'displacing the material of the side bar H to form the fiat locking surface 30, of the locking lug 12. By inspecting Figs. 4 and 5, it will be seen that rounded relief surfaces 3!,"32 and 33 are provided at the various places where the walls of the depression join with'the face of the side bar H The curved relief surface 33 is formed as a part of a circle represented .by the dash lines 34. Fig.4 also discloses the fact that a sharp corner or angle is avoided at the point where the fiat face 29 joins the semi-spherical surface of the depression 27 by thecurved surface or relief 35. V

The depth of the depression 27, of course, is determined by the amount of material which must be displaced to form the extruded lug l2. Regarding the diameterof the sphere, represented by the dash lines 28 in the several figures, it has been-determined that this diameter, so far as chain design is concerned, should not exceed the diameter of the pitch hole 86, although it may equal the pitch hole diameter or be smaller'than said pitch hole diameter.

By inspecting Figs. 2 to 5, inclusive, it will be seen that the lug .12 also is free from sharp angles and corners. The edges 36, see Figs. 2

and 5, are formed on flowing curves while the closedin Figs. l to 5,; inclusivawas finally adoptedas the commercial structure to be substituted for the fonmof depression, disclosed in Figs. 6

to 8, inclusive, avery'rigidtrial testwa made for the purpose of comparing therelative; strengths o-fthese twotypesof side b arst; Two chainassemblies, one including sidebars of the type dis-- closed in Figs. l-to .5, inclusive, andthe other includingside .bars of the type disclosed in Figs. 6 to 8, inclusive, were operated ,underfidentical conditions, each of which, simulated a 129.8

. horsepower drive. The first failure of a side in Figs. 1 to 5, inclusive, was operated for 535 hours before the first failure occurred in one of the side bars having a lug and depression of the inclusive.

character disclosed in Figs. 1 to 5, inclusive. However, during this 535 hour test, two of the plain side bars, i. e., side bars of Fig. 1 which are not provided with locking lugs, had failed. This test was continued many hours beyond the 535 hour point when the firstxside bar with an extruded lug failed, but no more failures occurred in extruded side bars. The test finally had to be discontinued because other parts of the chain assembly had become so badly worn that the assembly could not have been employed 1 longer as a commercial installation. In comparing the timesat which the first failures oc-,

curred in these two different types of extruded side bars, it will be seen that the side bars of the character disclosed in Figs. 1 to 5, inclusive, operated close to seven times that of the assembly including extruded side bars of the type disclosed in Figs. 6 to 8, inclusive. As no additional failures occurred in sidebars 0f the character, disclosed in Figs. 1 to 5, inclusive, there are no figures to compare with theadditional five side bar failures of the type disclosed in Figs. 6 to 8, As two plain side bars failed in the 535 hour test, while onlyone extruded side bar failed, it would appear obvious that extruded side bars of the character disclosed in Figs. 1 to 5, inclusive, are not any weaker than side bars having no extruded lugs. 1 i

Although I have selectedv a chain link side bar to illustrate the advantages of the form of extruded lug disclosed in detail in Figs. 1 to 5, in

elusive, it is to be understood that I do not desire to limit my extruded lug development to chain links, because there are many other load bearing elements, such as shackles, clevices, and the like,

which employ articulating joint forming pins] that should be held against rotation during joint articulation, and in which the strength of the.

load bearing element may be materiallyreduced by the use of an improperly shaped depression resulting from the formation of an extruded, pin locking lug.

In attempting to arrive at a satisfactory explanation for the increased strength and fatigue resistance possessed by the extruded side bars of Figs. 1 to 5, inclusive, over the side bars of Figs. 6 r

wall into the depression.

normal chain stresses, causes overloading must havea tendency-toshear the'tmetal in making the, depression with its sharp corners and angles. However, after. more mature consideration,it appeared that. theincrease in life dueto the use of the semi-spherical tools was out of all proportion mtofwhat might be expected from merely rounding off. sharp corners and angles.

The followingaadditional explanation, therefore,

isgiven: i l

It is customary to assemble chain pins in the pitch holesiofside bars by a press fitting operation. The. pitchhole diameters are usually from .003. of, an. inch to .005 of an inch smaller than the ,diameterpof the'chain pins. Under conditions such as arefoundsin side bars having extruded lockinglugsclosely positioned with respect to the, pitch holes, there is necessarily more metal in some portions of the hole circumference than at others, and the metal displaced by: the press fitting will naturally go to the side of .the. pitchhole which presents the least reing this invention, the least amount of metal is located between the pitch hole and the depression, formed in extruding the locking lug. The press fit, therefore, tends to force this pin In the old design of side bar shown in Figs.

' ,6 to 8, inclusive, with the sharp corners or.

angles at the base of the depression, press fitting of the pin in the pitch hole will tend to produce, a pre-loading of shearing stress at the angleformed by the side walls and the bottom of the depression. This condition, when added to the and failure.

In the improved form of extruded side bar disclosed in Figs. 1 to 5, inclusive, there are no sharp corners or angles and the roundedsurface 35 'joins theflat face 29 with the semi-spherical wall of the depression. Due to the location of the semi-spherical depression with respect tothe flat face 29, the low point of the depression is not located at the line of connection between the flat face 29 and the curved wall of the depression but is located rearwardly or in spaced relation to the flat face 29. Therefore, stress concentration at the base of the flat face 29 is not so great as with the side bar structure disclosed in Figs.

the chain is subjected to normal loads.

It is to be understood that the form of this invention herewith shown and described is tobe taken as a preferred example of the same, and

'6to 8, inclusive, and failures do not occur when that various changes in the shape, size, and ar- 1. In a load bearing element, such as a chain link, the improvement which comprises a side bar having an aperture, a pin having a head formed with a flat surface received in said aperture, a lug projecting from a face of the side bar and having a fiat face formed thereon adapted to engage the fiat surface of the pin head to prevent rotation of the pin, and a depression formed in the body of the bar as a result of displacement of material of the bar to form said projecting lug, said depression, with the exception of a fiat wall portion, having the shape of a semisphere with its diameter not exceeding the diameter of thepin aperture.

2. In a load bearing element, such as a chain e link, the improvement which comprises a side bar having an aperture,"a pin having a head formed with a flat surface received in said aperture, a lug projecting from a face of the side bar and having a flat face formed thereon adapted to engage the fiat surface of the pin head to prevent rotation of the pin, and a depression formed in the body of the bar as a result of displacernent of material of the bar to form said projecting lug, said depression being free from sharp angles and corners and, with the exception of a flat wall portion, produced in forming the flat face on said lug, having the shape of a semisphere which is arranged so as to locate'the lowpoint of the depression in spaced relation to said flat wall.

-3. In a load bearing element, such as a chain link, a side bar having an aperture, a pin, havadapted to engage the fiat surface of the pin head to prevent rotation of the pingand a depression formed in the body of the bar as a result of displacement of material of the bar to form' said projecting lug, said depression-having a flat wall portion on the side of the depression closest to the aperture and arranged on a plane parallel to the plane of and produced in forming the flat face on said lug, the remainder of the depression taking the shape ofa semisphere which is joined to the flat Wall portion of the depression and to the adjacent flat outer face of the side bar by rounded surfaces, the semispherical portion of the depression being arranged so as to locate its low point in spaced relation to the flat wallpo'rtion of the depression to thereby lessen stress concentration where the fiat wall portion and the semispherical portion of the depression are joined.

CARL F. LAUENSTEIN. 

